Gender differences in oxidative and nitrosative stress parameters in kidney transplant patients on tacrolimus-based immunosuppression.

BACKGROUND: Cardiovascular (CV) morbidity and mortality rates are still higher after kidney transplantation than in general population. It is known that oxidative and nitrosative stress may contribute to the progress of CV disease in a post-transplant period, but still gender aspect has not been elucidated completely. The aim of this study was to analyze the gender differences in the oxidative and nitrosative stress parameters, as well as asymmetric dimethylarginine (ADMA) and symmetric dimethylarginine (SDMA) levels among kidney transplant patients on tacrolimus-based immunosuppression. METHODS: Our research included 35 patients (20 men and 15 women) with renal transplant and 25 healthy volunteers. Patients were on chronic immunosuppressive regimen, which included tacrolimus, mycophenolate mofetil and prednisone. In order to estimate oxidative and nitrosative stress, we determined plasma levels of thiobarbituric acid-reactive substances (TBARS), activity of catalase (CAT), levels of total (protein and non-protein) sulfhydryl (SH) groups, advanced oxidation protein products (AOPP), ADMA and SDMA, as well as nitrite/nitrate (NOx) ratio. RESULTS: TBARS, CAT and SH in plasma were significantly higher in male patients than in female patients (p < 0.05, p < 0.01 and p < 0.05, respectively). There were no gender-dependent differences in AOPP, ADMA, SDMA and NOx in kidney transplant patients. Correlation analysis, Pearson and Spearman, showed significant correlations between tested oxidative and nitrosative stress parameters in male kidney transplant patients. Alternatively, in female patients, there were no significant correlations between tested parameters. CONCLUSION: Our findings show that men might be more prone to oxidative damage than women. ADMA, the proven marker of CV morbidity and mortality, may be more significant in male kidney transplant patients concerning oxidative stress control of its level and function.

Influence of dialysis modality and membrane flux on insomnia severity in haemodialysis patients.

AIM: Insomnia is an important problem in dialysis patients. A greater prevalence of insomnia in chronic kidney disease compared with non-renal patients suggests a role for uraemic toxins in contributing to insomnia. The aim of this study was to examine if dialysis modality and membrane permeability is associated with the frequency and severity of insomnia in haemodialysis patients. METHODS: In our cross-sectional study, we evaluated 122 patients who were divided into three groups: on-line haemodiafiltration, high flux haemodialysis and low flux haemodialysis. The frequency and severity of insomnia was evaluated with the Insomnia Severity Index. RESULTS: Insomnia was present in 47.5% of all patients. The majority of patients who reported insomnia were receiving low flux haemodialysis (80%), followed by patients on high flux haemodialysis (43.6%) and haemodiafiltration (20.9%). Patients using low flux membranes, had a significantly higher Insomnia Severity Index (11.9 ± 6.6) compared with patients receiving high flux haemodialysis (6.8 ± 6.3) and haemodiafiltration (5.2 ± 7.0). The insomnia severity index did not differ between patients receiving high flux haemodialysis compared with on-line haemodiafiltration. CONCLUSION: This study indicates that different haemodialysis modalities are associated with insomnia and suggests a potential benefit of using high flux membranes.

How the duration period of erythropoietin treatment influences the oxidative status of hemodialysis patients.

BACKGROUND: End-stage renal disease is a state of enhanced oxidative stress (OS) and hemodialysis (HD) and renal anemia further augment this disbalance. Anemia correction with erythropoietin (EPO) may improve oxidative status. However, there is no evidence of time dependent effects of EPO therapy on redox status of HD patients. OBJECTIVE: The aim of this study was to evaluate whether the duration of EPO treatment may affect OS parameters in uremic patients. PATIENTS AND METHODS: 104 HD patients and 29 healthy volunteers were included. Patients were divided into 3 groups according to the duration of EPO treatment. Forth group consisted of HD patients without EPO treatment. Plasma and erythrocyte malondialdehyde (MDA, MDA(rbc)), reactive carbonyl groups (RCG), plasma sulfhydryl (-SH) groups and total antioxidative capacity (TAC) levels were evaluated. RESULTS: HD patients both with and without EPO treatment, showed a significant increase in all oxidative parameters without significance between EPO treated and -untreated group. The decrease in MDA and MDA(rbc) levels coincided with the duration of EPO treatment. A negative correlation was observed between the duration of EPO treatment and serum MDA (r=-0.309, p=0.003). Increasing periods of EPO treatment were associated with decrease in RCG, without significance between EPO groups. Increase in TAC accompanied increasing durations of EPO treatment, with EPO treatment for more than 24 months causing the most striking changes (p<0.05). There were no significant differences in -SH levels between EPO subgroups. CONCLUSION: Our results suggest that long term administration of EPO attenuated the lipid peroxidation process and restored the levels of antioxidants.

Influence of dialysis modality and membrane flux on quality of life in hemodialysis patients.

BACKGROUND: The quality of life in patients undergoing hemodialysis is significantly disturbed. There are data that hemodiafiltration (HDF) may be more effective than conventional hemodialysis in the removal of uremic toxins and may reduce frequency and severity of intradialytic and postdialysis adverse symptoms in patients. Also, some researchers suggest advantages of using high-flux membranes compared with low-flux. OBJECTIVE: The aim of this study was to examine whether hemodialysis modality and membrane flux, independent of membrane biocompatibility, make differences in quality of life in patients. METHODS: In our cross-sectional study, we evaluated 124 patients who were divided, based on therapy, into three groups: online HDF, high-flux hemodialysis, and low-flux hemodialysis. Data were collected using the Short Form-36 questionnaire combined with special questionnaire, which included demographic and clinically related questions. RESULTS: Health-related quality of life was better in patients on HDF compared with patients on hemodialysis, especially compared with low-flux hemodialysis patients in most of the scales and in both dimensions: physical component scale and mental component scale. There were no statistically significant differences in Short Form-36 domains between high-flux hemodialysis and low-flux hemodialysis. CONCLUSION: Our data suggest the potential advantages of HDF with regard to influence on quality of life, which is sufficient to justify further research in prospective and longitudinal study design.